Very nice looking engine! I love engine parts 
Can't wait to build my next one whenever that might be. Interesting choice on the short stroke based on what you say your goals are.
What is your cam choice and power goals? I'd say your powerband estimates are short by at least 500 rpm depending on cam selection.
I have a stock displacement ls3 with ported heads and a victor JR single plane with a 239/251@50, .625 lift, and 110+2 centers and it peaked power at 7400 rpm. Didn't take it any higher as the rotating assembly is still stock.
I think the new fast 102 with the medium or even short length runners would be a fantastic choice for your new powerplant!
Im glad you chimed in on this as its nice to have some insight from experience with other cam/engine packages.
I need somewhere around 500 rwhp for my class, give or take some as I have ballast to work with and my plan to remove a lot more weight from the car. My cam is actually pretty close to yours - 237/252@.050 .600/.600 111+4, ramp rate is not real aggressive either. Is yours a solid roller or hydraulic roller? With mine only being 331ci it should rpm well, albeit the stock intake will be my limiting factor as most with the stock intake peak about 7k that i have seen. I went with the shorter stroke/displacment to limit myself power wise and move the peak torque up.
My first choice intake wise is that new adjustable fast 102 but CPG says it won't be available until next year, I like the idea of playing with the runners and my electronic throttle controls. I can fit a holly single plane and 4150 throttle body with filter under my scoop so that is a thought as well but I loose the dbw which I dont want. So I figure see what it does and if I'm not happy make adjustments from there.
The cam is a comp hydraulic roller. They're not super aggressive lobes either. The lobes are the older LSR family. It would be absurd fun with a 6 speed in a street car.
I think you should be able to make 500whp no problem with a good intake on it. The stock intake may hold you back a little. I made 528whp through an auto with a high stall converter (although only about 3-4% slip), mufflers, and with a throttle stop under the carb that I know robs a little power from restriction.
What compression will you be running? My engine is only 10.4:1.
This is a very cool combination. I am tire limited on my drag car and we really want to build a de-stroked ls7 for it for the same reasons. 4.125 bore with a stock 3.625" stroke crank. Don't want any more torque in the car, but want another 100ish horsepower out of it. Would only gain about 11 cubes from a stock displacement ls3.
Being a 331 it's going to want the rpm's with that much cylinder head on top. I think it will make good power, but essentially be clipped on the top as you run into airflow restriction. Power should hold flat until it starts to fall off at higher rpm. Not necessarily a bad thing! When you can get a short runner intake on there it'll really scream! Should be a blast!! You're going to love it.
A good set of custom headers tuned for your powerband would be the next thing I'd look at.
